Living with his sister in Chicago, Garnett led Farragut to a 28–2 record and was named National High School Player of the Year by USA Today. He was also named Mr. Basketball for the state of Illinois after averaging 25.2 points, 17.9 rebounds, 6.7 assists and 6.5 blocks while shooting 66.8% from the field. In four years of high school, Garnett posted an impressive 2,553 points, 1,809 rebounds and 737 blocked shots. In high school, Garnett played alongside Ronnie Fields, who also became a professional basketball player. Garnett was named the Most Outstanding Player at the McDonald's All-American Game after registering 18 points, 11 rebounds, 4 assists and 3 blocked shots, and then declared himself eligible for the 1995 NBA draft. To mark the 35th anniversary of the McDonald's All-American High School Boys Basketball Game, Garnett was honored as one of 35 Greatest McDonald's All-Americans. Garnett's decision not to play college basketball was influenced in part by his failure to score well enough on the ACT to meet NCAA requirements for freshman eligibility. Garnett told Student Sports Magazine in 1995 that if he had attended college he would have chosen to play college basketball for the University of Maryland.
Garnett was drafted with the fifth overall pick in the 1995 NBA draft by the Minnesota Timberwolves, and became the first player to be drafted directly out of high school since 1975. Since joining the NBA for the 1989–90 season, the Timberwolves had not won more than 29 games in any season. In Garnett's rookie season, the Timberwolves were in the midst of a transition phase; they replaced Bill Blair with Flip Saunders as head coach early in the season, and made several trades. Garnett initially came off the bench in his rookie year, but moved into the starting lineup soon after Saunders became head coach and with the urging of Sam Mitchell. In the final 42 games of the year, averaged 14 points, 8.4 rebounds and 2.26 blocks as a starter. In his rookie year, Garnett and fellow newcomer Tom Gugliotta carried the scoring load. Garnett did not immediately leap to stardom as later prep-to-pro prospects such as Amar'e Stoudemire, LeBron James and Dwight Howard would, but he did have a very respectable rookie year. He was voted to the All-Rookie Second Team on averages of 10.4 points, 6.3 rebounds and 1.8 assists per game. Despite having some promising players, the Timberwolves suffered through their seventh consecutive sub-30 win season and failed to make the playoffs. At the time, Garnett was the youngest NBA player in history at 19 years and 11 months of age.